Cooler arrangement for an electrical or equipment cabinet having air-to-air heat exchanger cassettes

ABSTRACT

The invention relates to a cooling arrangement ( 12 ) for an electrical or appliance cabinet ( 1 ), which has a functional area ( 4 ) with a cross-sectional area which extends along a longitudinal axis ( 9 ), wherein appliances and/or devices which produce heat during the operation can be arranged or are arranged in the functional area ( 4 ), wherein the cooling arrangement ( 12 ) comprises a mounting arrangement ( 11 ) whose longitudinal axis ( 27 ) to which the cross-sectional area corresponds and which has a plurality of holders ( 13, 14 ) for respectively alternative holding of a closure element ( 47 ) or an air-to-air heat-exchanger cassette ( 15, 16 ), wherein the air-to-air heat-exchanger cassettes ( 15, 16 ) are designed such that, during operation of the cooling arrangement ( 12 ), a first fluid flow ( 25, 26 ), which is connected to the functional area ( 4 ), is formed through the respective air-to-air heat-exchanger cassette ( 15, 16 ) in each case and a second fluid flow ( 28, 29 ), which is separate from the first fluid flow and is connected to environmental air in the electrical or appliance cabinet ( 1 ), is in each case formed in each of the air-to-air heat-exchanger cassettes which are arranged in one of the plurality of holders ( 13, 14 ), in order to transmit heat from the first fluid flow ( 25, 26 ) to the second fluid flow ( 28, 29 ), wherein two of the plurality of holders ( 13, 14 ) are designed such that the air-to-air heat-exchanger cassettes ( 15, 16 ) which are arranged in these holders ( 13, 14 ) have outlet openings and/or inlet openings ( 22, 23 ) which are at a distance from one another along the longitudinal axis ( 27 ), for the respective first fluid flows ( 25, 26 ).

The invention relates to a cooling arrangement for an electrical or appliance cabinet, as claimed in the preamble of patent claim 1.

The expression electrical cabinet or appliance cabinet is intended to mean, in an entirely general form, all types of cabinets, housings, cabins or boxes which have an internal area or functional area which is sealed at least with respect to a fluid exchange, for holding electrical or electronic appliances and/or installations. Electrical or electronic appliances or other installations such as these produce heat during operation. In order to dissipate this heat from the interior of the functional area, cooling arrangements such as those mentioned initially are used in order to avoid overheating of the appliances and/or installations.

The amount of heat to be dissipated is highly dependent on the appliances and/or installations arranged in the functional area, and their method of operation. In addition, this energy is dependent on the environmental conditions, for example an ambient temperature, solar radiation at the installation location of the electrical or appliance cabinet, etc. In order to ensure adequate heat dissipation and to keep the amount of thermal energy introduced from the surrounding area low, known electrical or appliance cabinets are generally designed with double walls. An inner housing with inner walls and a cover as well as a base surrounds the functional area.

Outer walls at a distance from the inner walls and an outer roof of the electrical or appliance cabinet form a closed outer housing. This, however, frequently has openings in order to allow circulation of fluids, in particular of environmental air, between the inner housing, which surrounds the functional area, and the outer housing, in order to use this environmental air to dissipate heat which is emitted via inner walls which seal the internal area and/or via the cover.

Fans are frequently used in order to form or maintain such fluid flows. These represent a noise source. Since the permissible emission limit values for noise differ depending on the installation location of the electrical or appliance cabinet, it is necessary at locations with low emission limit values to effectively configure a heat exchange between the interior of the functional area, in particular a cooling fluid in the interior of the functional area, generally air, and the cooling fluid which surrounds the functional area. Air-to-air heat-exchangers have been proposed for this purpose in the prior art. The required cooling fluid flow rate can be reduced by use of an air-to-air heat-exchanger in which the overall surface area of the separating boundary surface between a first fluid flow and a second fluid flow, to which heat is intended to be transferred from the first fluid flow, is enlarged or has been enlarged, thus reducing the noise emission created by fans for the same or a better heat dissipation performance.

During the useful life of an electrical or appliance cabinet installation in the open air, the appliances and/or installations arranged in the functional area are frequently changed, that is to say replaced, or added to etc. When installing the electrical or appliance cabinet, the precise requirement for the amount of heat to be dissipated, and possibly also the permitted noise emission, can thus not be estimated, or can be estimated only inadequately. Economically, there is no point in designing each of the appliance and electrical cabinets for the maximum possible heat dissipation performance. In fact, it is worthwhile in each case matching them to the present requirements, which, in particular, are dependent on the nature and the operation of the installation appliances and installations.

DE 20 2006 013 162 U1 proposes, for this purpose, an apparatus with an air-to-air heat-exchanger in order to provide cooling air for an electrical cabinet, in which the cooling air flows in a fast air flow through a heat-exchanger cassette, and environmental air flows in a second air flow through the heat-exchanger cassette, and the two air flows are produced by fans. In this case, the apparatus has a mounting unit which can be fitted with a variable number of physically identical heat-exchanger cassettes and a variable number of physically identical fans. In the known apparatus, the plurality of physically identical heat-exchanger cassettes in the mounting unit are arranged parallel alongside one another.

The cooling requirements for different areas of the functional area are different, particularly in the case of elongated electrical or appliance cabinets. A newly installed electrical or appliance cabinet is initially provided, for example, only in one area with appliances or installations which produce heat during operation. Another area is completely empty, or, for example, is fitted with passive distribution installations, which do not produce any heat, or only a small amount of heat, during operation. However, it is possible in a subsequent fitting state for appliances and installations which produce heat also to be fitted in the functional area in this other area.

Even in the case of appliance cabinets which have already been installed and are retrospectively fitted with new appliances and/or installations, there is frequently a difficulty in ensuring adequate heat dissipation after such a fitting process, as well. In this case, the physical height which is available for a cooling arrangement is frequently limited.

The invention is therefore based on the object of providing a cooling arrangement for an electrical or appliance cabinet which allows better flexible matching of the cooling conditions to the respective requirements, and preferably has a small physical height.

According to the invention, the object is achieved by a cooling arrangement having the features of patent claim 1. Advantageous refinements of the invention are specified in the dependent claims.

In this case, a cooling arrangement is proposed for an electrical or appliance cabinet which has a functional area with a cross-sectional area which extends along a longitudinal axis, wherein appliances and/or devices which produce heat during the operation can be arranged or are arranged in the functional area, wherein the cooling arrangement comprises a mounting arrangement whose longitudinal axis to which the cross-sectional area corresponds and which has a plurality of holders for respectively alternative holding of a closure element or an air-to-air heat-exchanger cassette, wherein the air-to-air heat-exchanger cassettes are designed such that, during operation of the cooling arrangement, a first fluid flow, which is connected to the functional area, is formed through the respective air-to-air heat-exchanger cassette in each case and a second fluid flow, which is separate from the first fluid flow and is connected to environmental air in the electrical or appliance cabinet, is in each case formed along the longitudinal axis in each of the air-to-air heat-exchanger cassettes which are arranged in one of the plurality of holders, in order to transmit heat from the first fluid flow to the second fluid flow. In order to achieve this object, it is proposed that two of the plurality of holders are designed such that the air-to-air heat-exchanger cassettes which are arranged in these holders have outlet openings which are at a distance from one another along the longitudinal axis, and/or inlet openings, which are at a distance from one another along the longitudinal axis, for the respective first fluid flows. It is thus possible to deliberately form first fluid flows in different areas along the longitudinal axis of the elongated cross-sectional area of the functional area. Fitting of the cooling arrangement with air-to-air heat-exchanger cassettes can thus be chosen to match the items fitted in different areas along the longitudinal axis of the functional area. Only those areas in which a particularly large amount of heat is produced during operation of the installed appliances and/or devices are also provided with an air-to-air heat-exchanger cassette. Other areas which do not result in stringent heat dissipation requirements need in contrast to be fitted only as appropriate.

Particularly when a plurality of adjacent areas in the functional area require good cooling, it has been found to be particularly advantageous for the plurality of holders to be arranged such that during operation the first fluid flows are in each case formed in air-to-air heat-exchanger cassettes which are arranged in adjacent runs of the plurality of holders along the longitudinal axis, and these fluid flows are directed in opposite directions parallel to the longitudinal axis. This means that the first fluid flows flow in opposite directions in the air-to-air heat-exchanger cassettes which are arranged adjacent.

In an arrangement such as this, it is advantageous if the at least two of the plurality of chambers are arranged such that a first fan, which is arranged between the holders, can maintain or assist the first fluid flows or alternatively the second fluid flows through both respective air-to-air heat-exchanger cassettes which are arranged in the adjacent runs of the plurality of holders. In this embodiment, the cooling arrangement therefore comprises at least one first fan arranged between adjacent holders.

In order to obtain a high degree of flexibility for items to be fitted while nevertheless requiring only a small number of fans, it is advantageous that the first fan which is arranged between the two adjacent holders is controlled as a function of whether air-to-air heat-exchanger cassettes are fitted in these holders. If, for example, only one holder is fitted with an air-to-air heat-exchanger cassette, then the first fan can be operated with a low flow rate. In one particularly preferred embodiment of the invention, a first fan such as this arranged between two holders is a radial fan.

In one particularly preferred embodiment of the cooling arrangement, the mounting arrangement is in the form of a cover element on the functional area. The mounting arrangement is designed such that it hermetically seals the functional area of the electrical or appliance cabinet at the top. This ensures that the functional area is completely dust and moisture proof, within the meaning of the chosen IP degree of protection. Furthermore, optimum heat dissipation and control of the first fluid flows in the functional area are possible. The air which is heated in the functional area (internal area) of the inner housing rises upwards. The highest temperatures of the surfaces which bound the internal area therefore occur on the cover of the functional area. A cooling arrangement can therefore be particularly effectively formed on the cover, or may be in the form of a cover element.

In preferred appliance or electrical cabinets, the inner housing has a frame which is created from profiles and generally has planking on the outside. The planking with inner walls and a cover is provided in such a way that the internal area is sealed against dirt, moisture and fluid exchange. In one preferred embodiment, in which the cooling arrangement is in the form of a cover element, the mounting frame has a circumferential contact surface which can be mounted on the frame.

In general, electrical or appliance cabinets have a functional area with a rectangular shape which is elongated along the longitudinal axis of the cross section. In one preferred embodiment, the mounting arrangement therefore has a circumferential rectangular elongated contact surface and the outlet openings of the air-to-air heat-exchanger cassettes which are arranged in the adjacent runs of the plurality of holders face opposite short end faces of the rectangular contact surface. The contact surface is designed such that it rests on the frame, which is formed from profiles, of the functional area and can be attached by attachment means. In order to ensure sealing with respect to dust and moisture as well as fluid exchange, circumferential seals can be introduced into the frame or frame profiles of the functional area. Alternatively, these seals can be integrated on or in the contact surface of the mounting frame.

If the outlet openings of the air-to-air heat-exchanger cassettes which are arranged in the adjacent runs of the plurality of holders each point towards the opposite short end faces of the rectangular cross-sectional area of the functional area, then this makes it possible to form different first fluid flows in the interior of the functional area, which are preferably directed downwards along the side walls of the functional area which are arranged on the short end faces of the cross-sectional area of the functional area. Air which in the first fluid flows which has been heated by the appliances and installations in the functional area is sucked in in the center between the air-to-air heat-exchanger cassettes which are arranged in adjacent holders and is passed via guide plates to the inlet openings of the air-to-air heat-exchanger cassettes. An arrangement such as this offers the advantage that, even if one fan fails, the first fluid flows are maintained as a circulation between the air-to-air heat-exchanger cassettes since the outer side walls, which bound the functional area, are cooled by adjacent environmental air from the outside, which enters between the functional area wall and an outer housing. There is therefore an air flow directed downwards in the interior of the functional area, adjacent to the functional area side walls. The heated air rises in the interior, probably in the center, of the functional area upwards and enters the air-to-air heat-exchanger cassettes.

In one preferred embodiment, the air-to-air heat-exchanger cassettes have channels which are oriented vertically and parallel to the longitudinal axis of the mounting arrangement, through which channels one of the first fluid flows and one of the second fluid flows flows alternately, horizontally transversely with respect to the lateral axis. This ensures particularly optimum heat transfer, even when, for example, the fan which maintains the first fluid flows fails. The holders and the air-to-air heat-exchanger cassettes are preferably designed such that the channels of the air-to-air heat-exchanger cassettes through which the second fluid flows flow, that is to say environmental air, are directly adjacent to the functional area, at least on one end surface of the channels, or at least make thermal contact with a boundary surface of the functional area. Even when the first fluid flows become entirely or partially stationary in the channels of the air-to-air heat-exchanger, at least reduced heat dissipation occurs in an embodiment such as this through the end surfaces of the channels of the air-to-air heat-exchanger through which the second fluid flows flow.

In order to stimulate and/or to maintain the second fluid flows, second fans, which each drive or assist one of the second fluid flows, are arranged, preferably oriented on the longitudinal axis of the mounting arrangement, at mutually averted ends of the air-to-air heat-exchanger cassettes which are arranged in adjacent runs of the plurality of holders. The second fans are preferably radial fans.

In order to ensure a flat physical shape and nevertheless to improve the induction of environmental air, which flows in via openings in vertical side walls of the outer housing or via openings in vertical side surfaces of the outer roof into an intermediate space between the inner housing and the outer housing, the second fans are, in one preferred embodiment, mounted tilted with respect to a horizontal installation position. Ends of the rotation axes which point upwards, that is to say towards the outer roof, are designed to be further away from the holder along the longitudinal axis of the mounting arrangement than the ends of the rotation axes which point downwards, towards the internal area. The rotation axes of the second fans are therefore not oriented vertically. The upper ends of the rotation axes of second fans which are associated with two adjacent holders are tilted in opposite directions from the vertical. The tilt is most easily provided by using mounting supports of different height. The higher supports face the holder, and the lower supports are averted from the holder. Environmental air can therefore be inducted into the radial fan better from the averted side.

In order nevertheless to achieve a flat physical shape, the mounting arrangement preferably has depressions which (during operation) are arranged or formed under the contact surface of the mounting arrangement or under a plane on which the air-to-air heat-exchanger cassettes are arranged and placed. The depressions are preferably in the form of troughs. In the case of electrical or appliance cabinets which comprise a frame created from profiles, these depressions are preferably adapted such that the depth dimensions of the depressions do not exceed the profile thickness of the profiles.

First fans which suck in cooling fluid which has been heated in the internal area or functional area and feed into the air-to-air heat-exchanger cassette or cassettes are preferably arranged in a raised area with respect to a contact surface of the mounting frame or a contact surface of the air-to-air heat-exchanger cassettes. A first fan such as this is in the form of a radial fan into which cooling fluid which has been heated in the internal area flows from underneath from the internal area, if appropriate through a grid, in order to avoid unintended actions on the first fan during operation in the event of maintenance work, and is supplied at the side to the air-to-air heat-exchanger cassette or cassettes. A rotation axis of the first fan, which is in the form of a radial fan, is therefore aligned vertically during operation.

In order to protect the cooling arrangement against external influences, in one embodiment the cooling arrangement comprises an outer roof which closes the electrical cabinet or appliance cabinet at the top, in which case the air-to-air heat-exchanger cassettes and the closure elements are matched to the outer roof such that they prevent the outer roof from bending in when forces act on the outer roof from above on the outside. This ensures that the cooling arrangement always operates. The air-to-air heat-exchanger cassettes and the closure elements are thus designed to be sufficiently robust that they can support the outer roof. This means that the strength on outer roof can be reduced and a portion of the structural robustness of the outer roof can be transferred to the air-to-air heat-exchanger cassettes or alternatively to the closure element inserted into the holders. Particularly preferably, the cooling arrangement with the outer roof forms a roof module.

The first and second fans are preferably in the form of radial fans. This results in the cooling arrangement and an outer roof arranged above it having a flat physical shape.

In order to optimally configure the air supply to the inlets of the air-to-air heat-exchanger cassettes, the fans in one embodiment are each surrounded by guide elements which drive air that has been sucked in by the fans in and/or into the corresponding channels of the air-to-air heat-exchanger cassettes.

The outer roof and/or the side walls of the outer housing are preferably formed in vertical sections with openings that are referred to as gills, in order to allow fluid of the second fluid flows to flow in and out.

All the fans, that is to say one or more first fans which are arranged in the functional area and second fans which drive second fluid flows of environmental air, are in one preferred embodiment driven and/or controlled via a common control device which faces the functional area. This offers the advantage that an electrical power supply via the control device can be provided via connecting lines in the interior of the functional area. Sealed passed-through connecting cables are formed with plug connectors for the individual second fans which are fitted on the side of the mounting arrangement averted from the functional area. Dependent on the requirement, second fans can therefore easily be fitted to the mounting arrangement and can be supplied with electrical power, in order to drive the second fluid flows.

The air-to-air heat-exchanger cassettes are designed such that, in conjunction with the outer roof, an inlet-flow area of the air-to-air heat exchanger cassettes is in each case separated from an outlet-flow area. This prevents the heated environmental air which emerges from an air-to-air heater-exchanger cassette from once again flowing into the same or an adjacent air-to-air heat-exchanger cassette. This ensures optimum cooling performance at all times. Only cool environmental air, which has not yet been heated, in each case flows as the second cooling fluid into the air-to-air heat-exchanger cassettes.

In one preferred embodiment, the plurality of holders are two holders which are designed such that, when two identical air-to-air heat-exchanger cassettes are arranged in the two holders, the first fluid flows are formed in the functional area such that they cool different areas, which are of the functional area.

The fans that are used are each arranged in front of inlet openings of the air-to-air heat-exchanger cassettes and blow the respective fluid flows into the air-to-air heat-exchanger cassettes.

The invention will be explained in more detail in the following text in conjunction with a drawing, in which:

FIG. 1 shows a schematic illustration of an appliance cabinet with a cooling arrangement;

FIG. 2 an exploded view of cooling arrangement with a heat-exchanger cassette and a closure plate; and

FIG. 3 shows a schematic view of a cooling arrangement with two heat-exchanger cassettes arranged adjacent to one another.

FIG. 1 schematically illustrates an appliance cabinet 1 which preferably has double walls. Other embodiments may, however, be formed with single walls. The appliance cabinet therefore comprises an outer housing 2 which surrounds, at a distance, an inner housing 3 which surrounds a functional area 4. The inner housing 3 is arranged on a base 5 which can be introduced partially or entirely into the ground. In other embodiments, the base is not introduced into the ground.

In one preferred embodiment, the inner housing 3 has a frame 6 which comprises individual profiles 7, which are attached to one another, preferably by being screwed to one another. The frame 6 has planking comprising functional area side walls 8, on the sides. The appliance cabinet 1 has a cross-sectional shape which is elongated along a longitudinal axis 9, preferably a rectangular cross-sectional shape. The functional area side walls 8 therefore preferably comprise short end faces 8 a and a longitudinal side wall which is frequently referred to as a rear wall 8 b. A front longitudinal side wall (not illustrated) facing the viewer is preferably in the form of a door. The functional area is also dust proof and fluid proof, and is therefore also sealed to be moisture proof, with respect to the base, that is to say downwards. Preferably sealed bushings for electrical power, data lines, glass fiber cables etc. are formed in a bottom 10, which seals the functional area at the bottom. At the top, the functional area 4 is sealed by a mounting arrangement 11 of a cooling arrangement 12. For this purpose, the mounting arrangement 11 is designed such that it forms a contact surface 46 which rests on the profiles 7 of the frame 6 and hermetically seals the functional area 4 such that it is dust proof and fluid proof. In this case, individual components of the cooling arrangement may “penetrate” or “project” into the functional area 4. This means that they are arranged underneath the contact surface 46 during operation. The mounting arrangement 11 of the cooling arrangement 12 is designed such that it can be attached and locked to the frame 6 with the aid of attachment means. Attachment means that are known to a person skilled in the art may be used as attachment means. For example, the mounting arrangement can be screwed to the frame 6.

The mounting arrangement 11 comprises two holders 13, 14 in which air-to-air heat-exchanger cassettes 15, 16 are arranged. These are arranged in the holders 13, 14 in such a way that it is impossible for fluid and/or dust to enter the functional area or to emerge from the functional area. In addition to the air-to-air heat-exchanger cassettes 15, 16, the cooling arrangement 12 comprises, on a side 17 facing the functional area 4, a first fan 18 which is preferably in the form of a radial fan. The first fan 18 is arranged in a projection 48 on the mounting arrangement 11. During operation, the projection is arranged above the contact surface 46. A first guide plate 19 is arranged around the fan and supplies first fluid 20, 21, which enters the radial fan and is heated in the functional area 4, through inlet openings 22, 23 to the air-to-air heat-exchanger cassettes 15, 16. First fluid flows 25, 26 are therefore formed in the air-to-air heat-exchanger cassettes 15, 16 and are directed parallel to the longitudinal axis 9 or a longitudinal axis 27 of the mounting arrangement, in opposite directions. Driven by the first fan 18, the first fluid flows 25, 26 flow through channels, which extend parallel to the longitudinal direction and vertically, in the air-to-air heat-exchanger cassettes 15, 16. Second fluid flows 28, 29 flow in the opposite direction through the air-to-air heat-exchanger cassettes 15, 16. These are driven by second fans 30, 31, which are preferably likewise in the form of radial fans. The second fans 30, 31 are mounted inclined so as to make it easier for environmental air to flow into the fans 30, 31. Further guide plates 32, 33 are arranged above the radial fans and supply the air to the further inlet openings 34, 35 of the air-to-air heat-exchanger cassettes 15, 16. The further guide plates 32, 33 have openings 61 which are aligned with inlet-flow areas of the second fans 30, 31, which are in the form of radial fans.

The cooling fluid of the second fluid flows 28, 29 is environmental air which enters and emerges from the outer housing via slot-like openings 36, which are referred to as gills, in an outer roof 37. The outer roof 37 has ribs 38 which are adjacent to the air-to-air heat-exchanger cassettes 15, 16, in order to separate inlet areas 39, 40 in the roof area from a central outlet area 41. This prevents the environmental air that has already been heated from once again being sucked into the second fluid flow and being passed through the air-to-air heat-exchanger cassettes 15, 16.

The first fan 18 and the second fans 30, 31 are supplied with electrical power, and are regulated, by a common control device 42. The control device 42 is fitted on that side 17 of the mounting arrangement 11 which faces the functional area.

In the illustrated embodiment, essentially separate first fluid flows 25, 26 are formed in separate areas 43 and 44 in the functional area 4. Internal air which has been cooled down in the air-to-air heat-exchanger cassettes 15, 16 flows along the short end face walls 8 a of the functional area 4 downwards, and then rises from the bottom 10 of the functional area 4 along the appliances and installations (not illustrated) which are fitted in the functional area 4, and in the process is heated by the heat from these appliances and/or installations. The heated internal area air, which has risen to the cover on the functional area 4, is sucked in through the first fan 18, and is forced into the air-to-air heat-exchanger cassettes 15, 16 where the heated air from the functional area 4 emits the heat through the boundary walls of the mutually adjacent channels to the environmental air in the second fluid flows 28, 29, which are heated in the air-to-air heat-exchanger cassettes 15, 16, then flowing out of the central outlet area 41 through the outer roof 37.

In addition to the fluid flows that have just been described, further fluid flows may be formed, in particular between the functional area with walls 8, that is to say of the inner housing 3, and the walls of the outer housing 2.

FIG. 2 shows a schematic exploded drawing of one embodiment of a cooling arrangement. The same technical features are provided with identical reference symbols. The mounting arrangement 11 has an essentially elongated rectangular shape. A contact surface 46, which is likewise essentially rectangular, is formed circumferentially and is intended to rest on profiles 7 of a frame 6 of a functional area 4 (cf. FIG. 1). By way of example, aperture openings are provided in the circumferential contact surface 46, in order to hold attachment elements which, for example, are latched and/or screwed into grooves in the profile. The mounting arrangement 11 has two holders 13, 14, which are designed to hold an air-to-air heat-exchanger cassette 15 or a closure element 47. A first fan (not illustrated) which is in the form of a radial fan, is arranged between the holders 13, 14 and is covered at the top by a box-like projection 48, which can also be referred to as a cover for the mounting arrangement. The box-like projection 48 has openings 51, 52 to the holders 13, 14. An inlet opening 22 for the air-to-air heat-exchanger cassette 15 or the closure element 47 may be adjacent to these openings 51, 52. Each of the holders 13, 14 additionally has a further aperture opening 53, 54, which is open to the functional area and to which the outlet opening 55 of the air-to-air heat-exchanger cassette 15 or of the closure element 47 is adjacent. Both the air-to-air heat-exchanger cassette 15 and the closure element 47 are attached to the mounting arrangement 11 such that the openings 51-54 are sealed to be fluid proof. Air, which has been sucked in from underneath through the first fan in a functional area can thus emerge through the opening 51 in the cover through the air-to-air heat-exchanger cassette 15 which is arranged on the holder 13, which air can enter the inlet opening 22 of the air-to-air heat exchanger cassette 15 and can enter the functional area through the opening 53 from the air-to-air heat-exchanger cassette 15. The openings 52 and 54, which are linked to the holder 14, are sealed by the closure element 47.

In order to drive the second fluid flow through the air-to-air heat-exchanger cassette 15, a second fan 30, which is in the form of a radial fan, is arranged in the trough-like depression 56 in the mounting arrangement 11. This is arranged on a fan holder with supports 57, 58 which are not of the same length or are at different angles, in such a way that it is arranged at an angle towards a short side edge 60 of the mounting arrangement 11. A profiled further guide plate 32 is arranged above the second fan 30 and ensures that environmental air which flows in through a circular opening 61 in the further guide plate 32 and is inducted through the second fan 30, is passed to the air-to-air heat-exchanger cassette 15.

As can be seen clearly, as an alternative to the closure element 47, an air-to-air heat-exchanger cassette of identical design can be arranged in the second holder 14. It is likewise possible to mount a further second fan, which is arranged inclined, in a further trough-like depression 62 and to position an additional further guide plate above this, in a similar manner to the further guide plate 32. The further guide plates may have identical profiles.

FIG. 3 schematically illustrates an arrangement such as this in which two air-to-air heat-exchanger cassettes 15, 16 are arranged in the mounting arrangement 11. The figure schematically indicates the alternately arranged channels 63, through which the first fluid flow and the second fluid flow flow alternately in opposite directions, in order to transfer heat from the first cooling fluid flow to the second cooling fluid flow via the vertical partition walls 64 of the channels.

The channels 63 are each oriented along the longitudinal direction 27 of the cooling arrangement 11. The vertical walls 64 separate the individual channel 63, through which the first fluid flow and the second fluid flow flow alternately, preferably in opposite directions, along a horizontal transversely with respect to the longitudinal direction 27.

Lower horizontal walls 65 of the channels 63 are preferably directly adjacent to the functional area of the inner housing, or make thermal contact with the functional area via a contact surface 66 of the mounting arrangement 11 (see FIG. 2). This ensures at least reduced cooling of the functional area even in the event of failure of the first fan.

A control device, which is arranged on the side of the mounting arrangement facing the functional area, is preferably designed such that it supplies an electrical power and regulates the first fan and the second fan. In this case, the control device is preferably designed such that a speed of revolution of the first fan, which sucks in heated air from the functional area, is defined as a function of the items fitted in the adjacent holders. If only one holder is occupied by an air-to-air heat-exchanger, then a reduced rotation speed is required from the first fan when the further environmental parameters are otherwise identical than if an air-to-air heat-exchanger cassette were fitted in both holders.

The described embodiment is only of an exemplary character. In other embodiments, further holders can be provided along the longitudinal axis of the mounting arrangement. This makes it possible to provide further areas, which are adjacent along the longitudinal axis, of the functional area with a separate cooling air supply. Since cooling air enters the functional area at different points along the longitudinal axis, different cooling flows can be passed to appliances and devices which require special cooling, via guide plates which are fitted in the interior of the functional area. Other parts of the internal area which may not require special cooling can be largely separated by guide plates (not illustrated) in such a way that the internal area air circulates effectively in the area in which the heat is produced by the installed appliances and installations.

List of reference symbols

1 Appliance cabinet

-   2 Outer housing -   3 Inner housing -   4 Functional area -   5 Base -   6 Frame -   7 Profiles -   8 Functional area side wall -   8 a End faces -   8 b Rear wall -   9 Longitudinal axis -   10 Bottom -   11 Mounting arrangement -   12 Cooling arrangement -   13, 14 Holders -   15, 16 Air-to-air heat-exchanger cassettes -   17 The side facing the functional area -   18 First fan -   19 First guide plate -   20, 21 First cooling fluid -   22, 23 Inlet openings -   25, 26 First fluid flows -   27 Longitudinal axis of the mounting arrangement -   28, 29 Second fluid flows -   30, 31 Second fans -   32, 33 Further guide plates -   34, 35 Further inlet openings -   36 Openings -   37 Outer roof -   38 Ribs -   39, 40 Inlet area (inlet-flow area) -   41 Outlet area (outlet-flow area) -   42 Control device -   43, 44 Areas -   46 Contact surface -   47 Closure elements -   48 Projection -   51-54 Openings -   55 Outlet opening -   56 Trough-like depression -   57, 58 Supports -   59 Fan holder -   60 Short side edge -   61 Circular opening -   62 Further trough-like depression -   63 Channels -   64 Vertical partition walls -   65 Lower horizontal walls -   66 Contact surface 

1. A cooling arrangement for an electrical or appliance cabinet, which has a functional area with a cross-sectional area which extends along a longitudinal axis, wherein appliances and/or devices which produce heat during the operation can be arranged or are arranged in the functional area, wherein the cooling arrangement comprises a mounting arrangement whose longitudinal axis to which the cross-sectional area corresponds and which has a plurality of holders for respectively alternative holding of a closure element or an air-to-air heat-exchanger cassette, wherein the air-to-air heat-exchanger cassettes are designed such that, during operation of the cooling arrangement, a first fluid flow, which is connected to the functional area, is formed through the respective air-to-air heat-exchanger cassette in each case and a second fluid flow, which is separate from the first fluid flow and is connected to environmental air in the electrical or appliance cabinet, is in each case formed along the longitudinal axis in each of the air-to-air heat-exchanger cassettes which are arranged in one of the plurality of holders, in order to transmit heat from the first fluid flow to the second fluid flow, wherein two of the plurality of holders are designed such that the air-to-air heat-exchanger cassettes which are arranged in these holders have outlet openings which are at a distance from one another along the longitudinal axis, and/or inlet openings, which are at a distance from one another along the longitudinal axis, for the respective first fluid flows.
 2. The cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the plurality of holders are arranged such that, during operation the first fluid flows are in each case formed in air-to-air heat-exchanger cassettes which are arranged in adjacent runs of the plurality of holders along the longitudinal axis, and these fluid flows are directed in opposite directions parallel to the longitudinal axis.
 3. The cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein at least two adjacent runs of the plurality of holders are arranged such that a first fan, which is arranged between the holders, can maintain or assist the first fluid flows or alternatively the second fluid flows through both respective air-to-air heat-exchanger cassettes which are arranged in the adjacent runs of the plurality of holders.
 4. The cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the first fan which is arranged between the two adjacent holders is operated as a function of whether air-to-air heat-exchanger cassettes are fitted in these holders.
 5. The cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the mounting arrangement is in the form of a cover element for the functional area.
 6. The cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the mounting arrangement has a circumferential contact surface.
 7. The cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the air-to-air heat-exchanger cassettes have channels which are oriented parallel to the longitudinal axis and through which, horizontally transversely to the longitudinal axis, one of the first fluid flows and one of the second fluid flows flows alternately.
 8. The cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein second fans, which each drive or assist one of the second fluid flows, are arranged, oriented on the longitudinal axis of the mounting arrangement, at mutually averted ends of the air-to-air heat-exchanger cassettes which are arranged in adjacent runs of the plurality of holders.
 9. Cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the cooling arrangement comprises an outer roof which closes the electrical cabinet or appliance cabinet at the top, in which case the air-to-air heat-exchanger cassettes and the closure elements are matched to the outer roof such that they prevent the outer roof from bending in when forces act on the outer roof from above on the outside.
 10. Cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the first and second fans are each radial fans.
 11. Cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the fans are each surrounded by guide elements which guide air that has been sucked in by the fans in and/or into the corresponding channels of the air-to-air heat-exchanger cassettes.
 12. Cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the outer roof has gills in order to allow the fluid of the second fluid flows to flow in and out.
 13. Cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the fans are driven and controlled via a common control device which faces the functional area.
 14. Cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the air-to-air heat-exchanger cassettes, in conjunction with the outer roof, each separate an inlet-flow area of the air-to-air heat-exchanger cassettes from an outlet-flow area.
 15. Cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the plurality of holders are two holders which are designed such that, when two identical air-to-air heat-exchanger cassettes are arranged in the two holders, the first fluid flows are formed in the functional area such that they cool different areas, which are adjacent along the longitudinal axis, of the functional area.
 16. Cooling arrangement for an electrical or appliance cabinet as claimed in claim 1, wherein the fans are in each case arranged in front of inlet openings of the air-to-air heat-exchanger cassettes, and blow the respective fluid flows into the air-to-air heat-exchanger cassettes. 